1. Field of the Invention
The present invention relates to apparatus for monitoring the environment of a floppy disk. More particularly, the invention relates to a defeat mechanism which prevents the use of a floppy disk cassette when it has been subjected to a potentially harmful high-temperature and/or high-humidity condition.
2. Description Relative To The Prior Art
A magnetic floppy disk will normally function properly over a relatively wide range of humidity and temperature conditions. When exposed to an excessively high temperature over a period of time, however, a magnetic oxide and a binder of the disk have a tendency to separate resulting in media failure or in extreme cases depositing binder on a magnetic head resulting in signal failure; high humidity likewise tends to accentuate both head and disk wear.
Ideally, each use of a disk would be at room temperature and relative humidity in a range near fifth percent. Unfortunately, this is not always feasible, so the limitations of the magnetic media must be considered and either adhered to or compensated for through increased cost such as by customizing the design of a disk drive mechanism.
The small size of a 3.5-inch floppy disk cassette makes it very portable. The ease with which a "micro" cassette can be transported potentially exposes the floppy disk to even more hostile environments including extreme moisture and temperature which can destroy existing data or make a disk system incapable of properly recording.